Earlier this week it transpired that Nvidia had begun to use new revisions of its AD103 and AD104 graphics processors for GeForce RTX 4080 and GeForce RTX 4070 add-in-boards (AIBs). Some thought the new revisions might reduce power consumption and/or increase yields, which could affect costs of actual cards. But Igor’s Lab claims that the new GPUs only have a built-in comparator for fans, which will have little effect on bill-of-materials (BOM) AIB costs.
Nvidia’s AD103-300 (used for GeForce RTX 4080) and AD104-250 (used for GeForce RTX 4070 and RTX 4070 Ti) graphics processing units require makers of graphics cards to add a comparator circuit which ensures that fans rotate at the right speed by comparing fans PWM signal with actual values, according to Igor’s Lab. The new AD104-251 and AD103-301 integrate the comparator into the GPU, which means that AIBs no longer need to carry external comparator circuitry.
Comparator circuitry is very cheap, so its removal will not affect BOM costs of actual graphics cards significantly, but board makers will probably still be eager to remove it and cut their costs — even by a bit. The savings from this removal will probably not be passed to the end user, however. In fact, since manufacturers will have to develop new PCB designs for AD104-251 and AD103-301 GPUs, which costs money, they will not be eager to lower their prices.
In fact, it is rather surprising that Nvidia decided to fix such a small bug like a disabled comparator using a new silicon revision at all (assuming that this is what happened as we know it from unofficial reports). Considering how complex modern GPU designs are, it is more likely for graphics processors developers to implement fixes that increase their yields or at least lower variability. Meanwhile, for both scenarios chip designers prefer to make small adjustments to process technology itself rather than introduce changes to actual silicon.
It should be noted that Nvidia has not formally disclosed differences between its AD103-251 and AD104-301 as well as AD103-250 and AD104-300 GPUs, so any information about this should be taken with a grain of salt. Also, an integrated comparator may not be the only change. For now it looks like the newer chips offer the same performance as the older ones, so there is no need to ensure that you get the new one.
At the end of the day, all GeForce RTX 4070 Ti and GeForce RTX 4080 graphics boards are still among the best graphics cards available today.